Concrete Cube Compressive Strength Test

Gold Owhere - Laboratory Analyst, Fundamental Integrated Site Appraisal Services (FISAS) Limited, Abuja

What is a concrete cube: A 150mm x 150mm x 150mm cube made/cast from concrete mix used in construction. The cube casts are cured for 7days and 28 days, and then tested in a compression testing machine to determine their compressive strength.

 What is compressive strength: Compressive strength is the capacity of material or structure to resist or withstand pressure under compression. It is ability of the material to resist failure in the form of cracks and fissure.

In performing the test, push force is applied on both faces of the concrete cube specimen. The maximum compression that cube bears without failure (peak strength) is recorded.

Compressive Strength =  Load Applied at Point of Failure/Cross-sectional Area of Cube

Compressive strength of concrete depends upon different factors like aggregate type/grading, water/cement ratio, proportion of constituents, workability, curing method, temperature, etc. The strength of the concrete increases with the age of the specimen.

 

Importance of concrete cube compressive strength test:

Through conducting this test, one can easily judge the concrete strength and quality of concrete produced.

The test result is used to determine if a concrete mix is fit for purpose. The result is also used to evaluate compliance of the concrete mix with design requirement.

 Concrete cube compressive strength test procedure:

  1. Remove specimen from water after specified curing time. Wipe out excess water from the surface.
  2. Measure dimension of the specimen and weigh
  3. Place and align specimen centrally on the base plate of the machine
  4. Apply load gradually and continuously till the specimen fails
  5. Record the maximum load and note any unusual features in the type of failure.

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